<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
       div{
          width: 100px;
          height: 100px;
          border: 2px solid red;
          /* 加了之后就不独占一行了 */
          display:none;
       }
       span{
          width: 100px;
          height: 100px;
          border: 2px solid red;
          /* 默认行内元素的width和height不起作用 */
          /* display变为块元素 */
          /* inline-block:既是行内元素也是块元素
             none:消失
           */
          display:inline-block;
       }
    </style>
</head>
<body>
    <div>div块元素</div>
    <span>span行内元素</span>
</body>
</html>